You suspect a virus has entered your computer. What will not be affected by the virus?
Answer: A
Correct answer: CMOS
A virus infects things that are read as programs or as file data - the boot sector, program files, the contents of floppies. The CMOS holds only the setup values (date, drive types, boot order) and is never executed, so a virus has nothing to infect there.
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Which page replacement algorithm gives the lowest possible page fault rate but cannot be implemented in practice ?
Answer: B
Correct answer: Optimal
The optimal algorithm replaces the page that will not be needed for the longest time ahead, which requires knowing the future reference string. It cannot be implemented, but it serves as the benchmark against which FIFO and LRU are measured.
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What is a TSR?
Answer: B
Correct answer: terminate and stay resident program
A TSR returns control to DOS but leaves its code in memory, normally with an interrupt vector pointing into it, so it can be re-entered by a hot key or by the hardware event it services. It was the only way to get background behaviour out of a single-tasking system.
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The _____ command allows you to modify the default prompt to provide other information
Answer: A
Correct answer: prompt
The PROMPT command redefines what DOS displays before each command. Its codes stand for pieces of information - $p for the current path, $g for the greater-than sign, $t for the time - so PROMPT $P$G gives the familiar C:\DOS>.
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While working with MS-DOS, which command is used to display the contents of a file and pause the display after each screenful of information?
Answer: A
Correct answer: TYPE filename | MORE
TYPE writes the file to the screen without stopping, so its output is piped into the MORE filter, which pauses at the end of each screenful until a key is pressed. CAT and pg are Unix commands, not DOS ones.
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Indicate which is a pre-emptive scheduling algorithm
Answer: A
Correct answer: Round-robin
Round robin is preemptive by definition: a process still running when its time slice expires is interrupted by the timer and moved to the back of the queue. Shortest-job-next and simple priority scheduling let the chosen process run to completion or to a block, so they are not preemptive.
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What command would you type to list all of the files in the current directory?
Answer: A
Correct answer: DIR
DIR lists the files and subdirectories of the current directory, with their sizes and dates. Its switches control the format: /W for a wide listing, /P to pause each screenful, /S to include subdirectories.
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What DOS program can you run to see which serial ports are detected?
Answer: B
Correct answer: MSD
MSD - Microsoft Diagnostics - reports what the machine contains: processor, memory, video, disk drives, and the COM and LPT ports it detects, with their addresses and settings. It reads the hardware and reports; it changes nothing.
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While using the DIR command, you can use certain switches with it. Which one of the following cannot be used with DIR?
Answer: D
Correct answer: /T
DIR accepts /P to pause by screenful, /W for a wide listing, /S to descend into subdirectories, and switches for sorting and attributes. There is no /T switch.
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When MS-DOS formats a disk, it automatically creates the main directory on your disk, which is called the _____ directory.
Answer: B
Correct answer: root
Formatting creates one directory on the disk, the root, written as \. Every other directory is created inside it or inside one of its descendants, so the root is the base of the whole tree.
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